Steam engine with a Reuleaux triangle instead of an eccentric.
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mistairjoe
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Yes it is. I am trying to understand this contraption myself. The lever on the bottom barelly moves the center weight by about 3/8. ad frankly I do not understand the function of the lever. I will be redesigning the support for the whole thing because it is cast in pot metal and it is flimsy.
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All about ball speed.... not mass. Massive balls for low speed, but small balls for faster governors.
It's not just about balls, but about the struts and geometry to get the appropriate stroke of the motion.
Newton devised the laws, then explained it by calculating mass and speed of the planets in orbit.
The motion derived from the governor is then following simple laws of levers (developed by Euclid?) to balance valve pressure and motion of the steam valve. I.E. Forces must be balanced by the mechanical advantage, or Motion balanced by the velocity ratio. Depends on the valve design. (It's what designers do...).
Aright guv'nor?
K2
It's not just about balls, but about the struts and geometry to get the appropriate stroke of the motion.
Newton devised the laws, then explained it by calculating mass and speed of the planets in orbit.
The motion derived from the governor is then following simple laws of levers (developed by Euclid?) to balance valve pressure and motion of the steam valve. I.E. Forces must be balanced by the mechanical advantage, or Motion balanced by the velocity ratio. Depends on the valve design. (It's what designers do...).
Aright guv'nor?
K2
I like the Reuleaux triangle. Just a mathematically improved eccentric to give a longer dwell at each end of the valve travel. Like a cam.
K2
K2
mistairjoe
Member
Thanks for the physics lesson K2. Are you saying that the governor was intentionally designed this way? The pot metal support does need a redesign being that it is flimsy but I can deal with that. Make a new one and cast it in bronze.
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Personally, I would trust the design. If intended as a whizz thing to entertain, it won't be connected to the steam throttle. But if designed as functional, then well lubricated, without sloppy bearings, it should function. So "suck it and see" is my best suggestion. Or reverse engineer by doing all the calculations of the drive train, forces, masses, levers, etc. A set of drawings would help this task!
K2
K2
Mechanical governors are more complicated than they may seem. It took a mathematician of the genius of James Clerk Maxwell to explain them properly, in his paper "On Governors", of 1868.
mistairjoe
Member
Well.. nothing was connected to the steam throttle. There was a lever but it was free of anything. As far as drawings, there are none. I have a feeling that this was an engineers project but there are some things that were mass produced looking at the lettering on the valve chest.
Tim Wescott
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Mechanical governors can be more complicated than they appear. But the ones in hit & miss engines are pretty simple in operation, getting you down pretty much to the mathematical complexity of the thermostat in a stove.
I love that article, BTW. I want busts of Newton, Maxwell and Einstein in my office -- I just can't find them for affordable prices.
Hi Joe.
It sounds to me like a proper "toy" manufacturer's model. Due to the die castings. A "toy" maker would make a governor perhaps more to look right than functional. So a "Whizzy, non-functioning" governor is quite likely. It would be driven by a belt and move a dummy lever. But the throttle may not exist that the lever should operate. Due to model scaling, and squares, cubes, etc. not working out well, I have seen many "Toys" set to look good but have non-functioning elements. Mamod do a lot of "tools" for the "tool-room" that are non-functioning. Not something I was allowed as a child. I had to use proper tools from the outset! A treadle lathe (My sister operated the treadle by hand while I tried to turn a brass screw in the chuck - legs too short to reach!), an hand-wound grindstone, etc. files, a pin hammer (because it was small enough for a small child). But real tools. Then my grandfather showed my how to do things with his watch-making tools. - I could handle things well with my small hands that he struggled with his big hands and fingers! I used to collect all the dropped parts off the floor for him. We should all have a useful grandchild in the workshop for the small things...
K2
I just love old engines like this. There is a full scale engine at the Renolds Museum in Witaskiwin, Alberta. The flywheel is two stories high. The operation is slow but watching it operate is a reminder, not all engines have to run at high RPM to be effective. Thanks for reminding all of us of a simpler method and times.
Mike1
Mike1
I can't see the detail of the throttle on top of the steam chest. It just looks like a big industrial nut for a steam pipe connection? But if it has/had a throttle, it is likely that it was connected to the governor. the alignment looks right between the lever and the steam intake on the valve chest. You just need to design the "missing link" and make a throttle.
What are the relative diameters of the pulleys? (Crankshaft to governor?).
I guess this engine was designed to run on about 5psi min, but 40psi max. (if driving a dynamo or something?). - What boiler do you have and what are your plans? - Typically I run at 10psi for an engine like this as it looks better idling slowly rather than hammering around like a sewing machine! Which probably means the governor will be redundant: I.E. You'll connect the belt and it will rotate, but not run fast enough to operate a throttle valve.
Personally. I would lubricate the eccentric with a good quality Lithium grease, or Molybdenum grease, as the fast valve action from the Reuleaux triangle relies upon small rubbing surfaces, which will be prone to wear.
Providing it all seems to work when you turn the flywheel, give it a good oiling at all the oilers and all the other bearings (even into the intake to the valve chest to lubricate the valve and get into the cylinder, but keep the cylinder drains open so you can tell that the oil has worked all the way in) and wind the flywheel around for a few dozen turns. Only then apply a few psi of compressed air (no more than 10psi should be plenty of pressure!). Then sit and watch it for a while... Even post a video of the valve motion? I am sure many would like to see that in action?
When you finish, a good wipe with the "oily rag" helps prevent surface rust forming on all the unpainted steel. Not grease, as this tends to "stick" after it has been sat a little while.
After steaming, I squirt WD40 into the intake and pump it through the cylinder to clear the water... But then you must apply a good oil (low viscosity car engine oil is full of corrosion resisting additives) to wash out the acid WD40. (WD 40 is an acidic water repellent, good for getting rid of water and surface rusting, but for corrosion protection you need an alkali oil - like motor oil).
ENJOY!
K2
What are the relative diameters of the pulleys? (Crankshaft to governor?).
I guess this engine was designed to run on about 5psi min, but 40psi max. (if driving a dynamo or something?). - What boiler do you have and what are your plans? - Typically I run at 10psi for an engine like this as it looks better idling slowly rather than hammering around like a sewing machine! Which probably means the governor will be redundant: I.E. You'll connect the belt and it will rotate, but not run fast enough to operate a throttle valve.
Personally. I would lubricate the eccentric with a good quality Lithium grease, or Molybdenum grease, as the fast valve action from the Reuleaux triangle relies upon small rubbing surfaces, which will be prone to wear.
Providing it all seems to work when you turn the flywheel, give it a good oiling at all the oilers and all the other bearings (even into the intake to the valve chest to lubricate the valve and get into the cylinder, but keep the cylinder drains open so you can tell that the oil has worked all the way in) and wind the flywheel around for a few dozen turns. Only then apply a few psi of compressed air (no more than 10psi should be plenty of pressure!). Then sit and watch it for a while... Even post a video of the valve motion? I am sure many would like to see that in action?
When you finish, a good wipe with the "oily rag" helps prevent surface rust forming on all the unpainted steel. Not grease, as this tends to "stick" after it has been sat a little while.
After steaming, I squirt WD40 into the intake and pump it through the cylinder to clear the water... But then you must apply a good oil (low viscosity car engine oil is full of corrosion resisting additives) to wash out the acid WD40. (WD 40 is an acidic water repellent, good for getting rid of water and surface rusting, but for corrosion protection you need an alkali oil - like motor oil).
ENJOY!
K2
Richard Hed
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Oh great. Thanx for the complicated calculus.
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